Sensing RF environment to determine geographic location of cellular base station

ABSTRACT

Determining a geographic location of a cellular base station is disclosed. In some embodiments, a set of measurement data that includes for each of a plurality of signals received at the base station a corresponding measurement data is determined. The set of measurement data is used to determine the geographic location of the base station. In some embodiments, a set of measurement data is received. The received measurement data includes for each of a plurality of location measurement units at which a signal transmitted by the base station is received a corresponding measurement data associated with the signal. The set of measurement data is used to determine the geographic location of the base station.

CROSS REFERENCE TO OTHER APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationNo. 60/850,872 entitled Method of RF Monitoring, filed Oct. 10, 2006,which is incorporated herein by reference for all purposes.

BACKGROUND OF THE INVENTION

In a traditional mobile telecommunication network, mobile stations(e.g., mobile phones) communicate via an air link with a stationary basetransceiver station (BTS), typically a tower or other structure with oneor more antennas and associated radio transceivers. A traditional BTStypically relays data between mobile stations and the core mobilenetwork via a dedicated communication link to a base station controller(BSC). However, smaller base transceiver stations have been developed,e.g., for personal use in the home, dedicated use by a small business orother enterprise, dedicated or additional coverage for areas with highuser density or demand (such as airports), etc. Such smaller basetransceiver stations are sometimes referred to herein and in theindustry by a variety of terms, depending on their size andconfiguration, including without limitation by terms such as“micro-BTS”, “pico-BTS”, and “femto-BTS”, which terms distinguish suchsmaller scale installations from a traditional “BTS”, which is sometimesreferred to as a “macro-BTS” deployed to serve an associated“macro-cell”. Deployment of such smaller base transceiver stations poseschallenges to mobile telecommunications network operators and equipmentproviders, including the need to know that a deployed small scale BTShas not been moved without authorization to a location in which thesmall scale BTS is not authorized to operate.

In addition, certain regulatory and/or service requirements, such asemergency 911 (E911) regulations that require mobile telecommunicationsproviders to be able to provide to authorities the location from which acall from a mobile phone is being and/or was made, require that thelocation of the base station be known.

Therefore, there is a need for a way for a mobile network and/or serviceprovider to determine the geographic location of a small scale orotherwise potentially movable base station or other network equipment.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the invention are disclosed in the followingdetailed description and the accompanying drawings.

FIG. 1 is a block diagram illustrating an embodiment of a portion of amacrocellular network.

FIG. 2 highlights the region of overlap of the coverage areas shown inFIG. 1.

FIG. 3 is a block diagram illustrating an embodiment of a prior artcircular lateration approach used to determine the geographic locationof a mobile station.

FIG. 4 is a block diagram illustrating an embodiment of a portion of acellular network in which a small scale base station has been deployed.

FIG. 5 is a block diagram illustrating an embodiment of a micro-, pico-,and/or femto-BTS or other small and/or potential movable basetransceiver station with IP network backhaul.

FIG. 6 is a flow chart illustrating an embodiment of a process fordetermining a general geographic location of a small scale base stationor other potentially movable mobile network equipment.

FIG. 7 is a flow chart illustrating an embodiment of a process fordetermining a geographic location of a small scale base station or otherpotentially movable mobile network equipment.

FIG. 8 is a flow chart illustrating an embodiment of a process fordetermining a geographic location of a small scale base station or otherpotentially movable mobile network equipment based on the time ofarrival of a signal transmitted by the small scale base station.

DETAILED DESCRIPTION

The invention can be implemented in numerous ways, including as aprocess, an apparatus, a system, a composition of matter, a computerreadable medium such as a computer readable storage medium or a computernetwork wherein program instructions are sent over optical orcommunication links. In this specification, these implementations, orany other form that the invention may take, may be referred to astechniques. A component such as a processor or a memory described asbeing configured to perform a task includes both a general componentthat is temporarily configured to perform the task at a given time or aspecific component that is manufactured to perform the task. In general,the order of the steps of disclosed processes may be altered within thescope of the invention.

A detailed description of one or more embodiments of the invention isprovided below along with accompanying figures that illustrate theprinciples of the invention. The invention is described in connectionwith such embodiments, but the invention is not limited to anyembodiment. The scope of the invention is limited only by the claims andthe invention encompasses numerous alternatives, modifications andequivalents. Numerous specific details are set forth in the followingdescription in order to provide a thorough understanding of theinvention. These details are provided for the purpose of example and theinvention may be practiced according to the claims without some or allof these specific details. For the purpose of clarity, technicalmaterial that is known in the technical fields related to the inventionhas not been described in detail so that the invention is notunnecessarily obscured.

Sensing an RF environment to determine the geographic location of amobile telecommunications network asset, such as a small scale basestation, is disclosed. In some embodiments, a small scale base station,such as a micro-, pico-, or femto-BTS, includes an RF sensing or“sniffing” subsystem that enables the base station to sense the RFenvironment in a location in which the base station is located. In someembodiments, signals broadcast from sources the location of which isknown are sensed by the small scale base station or other potentiallymovable equipment, and triangulation and/or similar techniques are usedto determine the geographic location of the base station or otherequipment. In some embodiments, beacon or other signals broadcast byadjacent macrocells (macro-BTS's) are sensed and used to determine thegeographic location of the small scale base station or other equipment.

FIG. 1 is a block diagram illustrating an embodiment of a portion of amacrocellular network. In the example shown, each of the basetransceiver stations (BTS) 102, 104, and 106 has associated with it acorresponding geographic coverage area 108, 110, and 112, respectively,within which its signal is strong enough to be received and used by amobile station (MS) to communicate with the core mobiletelecommunication network via that BTS. In areas in which two or morecoverage areas overlap, an MS could in theory communicate with the coremobile network via any BTS having coverage in that area. In the exampleshown, a mobile station (MS) 114 is located in a region in which thecoverage areas 108, 110, and 112 overlap.

FIG. 2 highlights the region of overlap of the coverage areas shown inFIG. 1. The geographic location of the MS 114 can be determined to afirst order by concluding from the fact that the MS 114 is receiving therespective beacon or other broadcast signal being transmitted by BTS's102, 104, and 106 that the MS 114 is located somewhere in the region 202in which the coverage areas 108, 110, and 112 overlap. In someembodiments, the above approach is extended to potentially movablenetwork elements, such as a small scale base station. In someembodiments, a small scale base station senses the local RF environment.The general geographic location of the base station is determined byfinding the region(s) in which the coverage areas of the respectivemacro-BTS's from which the small scale base station or other networkequipment is receiving the beacon or other broadcast signal overlap.

FIG. 3 is a block diagram illustrating an embodiment of a prior artcircular lateration approach used to determine the geographic locationof a mobile station. In the example shown, the more precise geographiclocation of the MS 114 is determined by calculating the distance of theMS from each of the adjacent macro-BTS's 102, 104, and 106. Using atechnique known as Enhanced Observed Time Difference (E-OTD), forexample, the difference between a time at which the MS receives therespective signal burst from each of two (or more) pairs of macro-BTSsand the real time difference (RTD) that represents the time offsetbetween emissions of the respective signal bursts from the BTS's areused to determine the geographic location of the MS.

E-OTD can be performed in a couple of ways: hyperbolic or circular. Bothmethods require the MS to detect and process emissions from threedistinct BTSs. In the hyperbolic method, time-of-arrival differencesbetween BTS emissions, taking BTSs in pair-wise combinations, aremeasured at a location. A pair consists of a designated “reference” BTSand one neighbor BTS, from the reference cell's neighbor list. In someembodiments, for each reference BTS a list of base stations for whichnetwork assistance data has been compiled is obtained from a ServingMobile Location Center (SMLC), and a neighbor cell for which suchnetwork assistance data is determined to be available is included in thepair. More than three BTSs can be used for increased accuracy, but tosimplify the discussion, it will be assumed here that the MS uses areference cell (ref) and two neighbor cells (nbr1 and nbr2) for OTDmeasurements. The MS then makes Observed Time Difference (OTD)measurements for the three selected base stations, taken as two pairs:OTD(ref, nbr1) and OTD(ref, nbr2).

However, the OTD measurements made at the MS are not sufficient toestimate the MS position. The macro-network base stations are nottime-synchronized, causing the OTD measurement to include BTS timeoffsets, and not just the desired propagation delays required forgeometry calculations. To achieve a posteriori cell synchronization,additional Radio Interface Timing (RIT) measurements are made at aLocation Measurement Unit (LMU). Because the geographical locations ofan LMU and macro-BTSs are known, the Real Time Differences (RTDs) can bederived. An RTD represents the time offset between emissions from twodifferent base stations. The desired Geometric Time Difference (GTD),which is the time difference between the reception (by an MS) of burstsfrom two different base stations due to geometry, can be calculated asOTD−RTD. The necessary RTD values, along with a list of pairs of basestations and their geographical coordinates, are compiled into the E-OTDassistance data at a Serving Mobile Location Center (SMLC). An SMLC canbe associated with one or more LMUs. The SMLC assistance data and theMS's OTD measurements must be combined to estimate the position of theMS. This calculation can be made either at the SMLC or the MS.

Using E-OTD or similar techniques to determine the location of a smallscale or other potentially movable base station is disclosed. In someembodiments, a small scale or other potentially movable base station isconfigured to sense the local RF environment, for example by takingE-OTD measurements with respect to beacon and/or other broadcast signalstransmitted by adjacent macro-BTS's. The E-OTD measures are used todetermine a location of the small scale or other potentially movablebase station relative to the adjacent macro-BTS's, and the precisegeographic location of the small scale base station (e.g.,latitude/longitude, street address) is determined based on the knownlocation of the macro-BTS's.

FIG. 4 is a block diagram illustrating an embodiment of a portion of acellular network in which a small scale base station has been deployed.Each of the macrocell base transceiver stations (BTS) 102, 104, and 106has associated with it a corresponding geographic coverage area 108,110, and 112, respectively, within which its signal is strong enough tobe received and used by a mobile station (MS) to communicate with thecore mobile telecommunication network via that BTS. In areas in whichtwo or more coverage areas overlap, an MS could in theory communicatewith the core mobile network via any BTS having coverage in that area. Asmall scale base station 416 having an associated coverage area 418 hasbeen deployed, e.g., in a home or office, in a location such that thecoverage area 418 overlaps (and in this example, for clarity ofillustration, falls entirely within) the region in which respectivecoverage areas 108, 110, and 112 of BTSs 102, 104, and 106,respectively, overlap.

FIG. 5 is a block diagram illustrating an embodiment of a micro-, pico-,and/or femto-BTS or other small and/or potential movable basetransceiver station with IP network backhaul. In the example shown,macrocell BTS's 102, 104, and 106 communicate with the core mobilenetwork 504 via a dedicated land line (e.g., T-1/E-1) to a BSC 502. Thesmall scale BTS 416 is shown as being connected to BSC 502 via an IPnetwork 506 and an aggregation gateway (AGW) 508. In some embodiments,AGW 508 is configured to support one or more small scale BTS's such asBTS 416, aggregating their traffic and translating traffic sent via theIP network 506 using a suitable protocol, e.g., the real-time transportprotocol (RTP) for voice traffic, to the Abis (for GSM) or similarinterface to the BSC 502 (or equivalent node in a non-GSM network), andvice versa. In some embodiments, a special SMLC is dedicated to a groupof small scale base stations. In some embodiments, E-OTD or otherlocation determining functions typically performed by an SMLC todetermine the location of an MS are incorporated into the AGW 508. Ashigh-speed Internet access for homes and small businesses becomes moreand more ubiquitous, it has become and will continue to become more andmore possible to deploy small scale base stations in homes andbusinesses, and use IP backhaul to provide connectivity to the coremobile network, avoiding the cost and waste of bandwidth that wouldattend if each such base station required a dedicated T-1/E-1 or otherhigh capacity connection.

One challenge faced by mobile network providers in connection withdeploying, operating, and monitoring small scale base stations such asBTS 416 in the examples shown in FIGS. 4 and 5 is that such small scalebase stations may be small and light enough to be moved to a geographiclocation in which they are not authorized to be moved and/or from aspecified geographic location in which they are intended and configured(e.g., provisioned) to be used. In the example shown in FIGS. 4 and 5, asmall scale base station that it is physically possible to move could bemoved and, absent countermeasures, deployed and used in any locationhaving Internet access. For example, a small scale base station sold andintended for use in a home in one area could be resold and/or moved,without the network and/or service provider's permission, for use inanother location. If not properly configured and/or authorized, such usein another location (e.g., another country, or out of the provider'sservice area) may violate government regulations, spectrum or otherlicense and/or ownership rights of other providers, internationaltelecommunications rules and agreements, the national or local laws ofother countries, etc.; result in a loss of revenue and/or businessopportunity, e.g., to sell or lease a base station to a secondsubscriber at the location to which the small scale base station hasbeen moved; and/or facilitate a market for the sale and/or use of stolenbase station equipment.

In addition, if the base station 416 were moved to an unknown location,it may not be possible for the mobile network and/or service provider tocomply with E911 or other requirements and/or needs that require thatthe geographic location of the base station 416 be fixed or at leastknown. For example, if the base station 416 were moved to a locationother than a registered location, the mobile network and/or serviceprovider may not be able to determine accurately the geographic locationof a mobile station (MS) used to place a 911 or other call via the basestation 416.

GPS and other satellite based systems exist to determine and/or monitorgeographic location, but such transceivers are expensive and require aclear view of the sky, which may not always be available with respect toa small scale base station deployed in a home (e.g., apartment), office,or other commercial building.

Therefore, extending the techniques described above as being used todetermine the geographic location of a mobile station (MS) todetermining the geographic location of a small scale base station orother potentially movable mobile network equipment is disclosed.

FIG. 6 is a flow chart illustrating an embodiment of a process fordetermining a general geographic location of a small scale base stationor other potentially movable mobile network equipment. In variousembodiments, the process of FIG. 6 is implemented at least in part by asmall scale base station or other potentially movable mobile networkequipment and/or in part by another element, such as an elementcomprising and/or associated with the core mobile network. In theexample shown, the local RF environment is sensed 602. Based at least inpart on the sensed RF environment, a general geographic location of thebase station or other equipment is determined 604. The locationdetermined at 604 is compared to an authorized location of the basestation or other equipment 606. If the comparison indicates the basestation or other equipment has been moved to an unauthorized location608, e.g., because the authorized location is not in the general areadetermined at 604, responsive action is taken 610. Examples ofresponsive action include shutting down the base station or otherequipment, denying access to the core mobile network, and/or sending analert.

FIG. 7 is a flow chart illustrating an embodiment of a process fordetermining a geographic location of a small scale base station or otherpotentially movable mobile network equipment. In various embodiments,the process of FIG. 7 is implemented at least in part by a small scalebase station or other potentially movable mobile network equipmentand/or in part by another element, such as an element comprising and/orassociated with the core mobile network. In the example shown, E-OTD (orsimilar) measurements are taken 702. The measurements taken at 702 andthe known location of each respective macro-BTS are used to performhyperbolic (or circular) lateralization to determine a (relatively)precise geographic location of the small scale base station or otherequipment 706. The location determined at 706 is compared to anauthorized location 708. If the location determined at 706 is not the(or a) location in which the small scale base station or other equipmentis authorized to operate 710, responsive action is taken 712.

In some embodiments, 602-604 of FIG. 6 and/or 702-706 of FIG. 7 are usedto determine (or verify) a current location of a small scale basestation or other equipment, e.g., for purposes of using the determined(or verified) position of the base station to determine in turn alocation of a mobile station (MS) or other equipment based at least inpart on E-OTD or other measurements taken with respect to a beacon orother broadcast signal associated with the small scale base station orother equipment and/or to determine the general geographic location ofan MS or other equipment that has sensed a beacon or other broadcastsignal associated with the small scale base station or other equipment.

In some embodiments, the geographic location of a small scale basestation is determined at least in part by prompting the small scale basestation to transmit a signal burst and computing time differences in thearrival of the signal burst at one or more LMUs. A similar technique,known as Uplink Time Difference of Arrival (U-TDOA or U-TDoA) is used insome mobile networks to determine the geographic location of a mobilestation (MS). U-TDOA is a method for location positioning of a MobileStation (MS) that essentially operates in the reverse direction ascompared to E-OTD, and requires no changes to be made to a handset orother mobile equipment. In E-OTD, downlink transmissions from at leastthree geographically distinct BTSs must be measured at the handset (orother equipment) in question. By contrast, in U-TDOA, uplinktransmissions from the handset (or other equipment) must be measured byat least three geographically distinct network LMUs. The LMUs eachmeasure an observed “time of arrival” (TOA) of the handset transmissionbursts and forward their data to the SMLC. The SMLC calculates “TimeDifference of Arrival” (TDOA) by pair-wise subtracting the TOA values.The SMLC also knows the geographical coordinates of the LMUs and thetime offsets, if any, among LMU clocks. Using all of this data, the SMLCcalculates the position of the handset.

The MS does not perform any unusual processing specific to U-TDOA duringthis procedure. If the MS was already in dedicated mode at the start ofthe location process, then the MS's TCH uplink bursts are measured atthe LMUs. If the MS was in idle mode, then the MS is placed in dedicatedmode by the MSC/BSC, specifically for location purposes, and either theSDCCH or TCH can be used for uplink transmission in that case.

Note that both U-TDOA and E-OTD employ an SMLC and multiple LMUs, andboth use the hyperbolic positioning method.

In some embodiments, to support U-TDOA a small scale base stationconfigured to transmit uplink bursts to the macro-network. Thetransmission power must be of sufficient strength for the necessarytime-of-arrival measurements to be made at multiple network LMUs. Insome embodiments, the small scale base station acts like a handset withrespect to the macro-network—i.e., exchange signaling information to setup a call using specified physical channel parameters, and transmituplink bursts on the SDCCH or TCH. In some alternative embodiments, aportion of the call setup signaling exchanges (prior to the SDCCH/TCHuplink bursts) are accomplished over proprietary interfaces via theInternet. In some embodiments, GSM (or other mobile) handset transceiverfunctionality is incorporated into the small scale base station. In someembodiments, a special SMLC is dedicated to a group of small scale basestations.

FIG. 8 is a flow chart illustrating an embodiment of a process fordetermining a geographic location of a small scale base station or otherpotentially movable mobile network equipment based on the time ofarrival of a signal transmitted by the small scale base station. Thesmall scale base station (or other potentially movable network element)is prompted to transmit (802). The signal the small scale base stationwas prompted to transmit is received (804). In some embodiments, thesignal is received at three or more LMUs. A location of the small scalebase station is determined based on time or arrival of the receivedtransmission, e.g., at the respective LMUs (806). In the example shownin FIG. 8, if the location determined at 806 is an unauthorized location(810), responsive action is taken (812); otherwise the process ends.

In some embodiments, the location of a small scale base station isdetermined by using uplink transmissions from one or more MSs beingserved by that base station, whether through normal uplink trafficbursts from an MS to the base station, or by forcing the MS into atemporary handover state to a macro-BTS (on that MS's neighbor celllist). The network LMUs detect these uplink transmissions, after beinginformed of the physical channel information by the SMLC in the normalway.

While a number of the examples described herein refer to GSMtechnologies, such as E-OTD and U-TDOA, in various embodiments otherlocation determination techniques used previously to determine thelocation of a mobile equipment are applied to determine the location ofa small scale base station or other mobile network equipment. Forexample, in a UMTS network, in various embodiments Observed TimeDifference of Arrival (OTDOA) and/or other techniques defined and/orsupported by applicable standards are used.

Although the foregoing embodiments have been described in some detailfor purposes of clarity of understanding, the invention is not limitedto the details provided. There are many alternative ways of implementingthe invention. The disclosed embodiments are illustrative and notrestrictive.

What is claimed is:
 1. A method of determining a geographic location ofa small scale base station, the method comprising: querying, by smallscale base station, a serving mobile location center (SMLC) to determinea reference macro-base transceiver station (macro-BTS) and a neighbormacro-BTS of the reference macro-BTS; receiving a plurality of signalsat the small scale base station including a first signal transmitted bythe reference macro-BTS and a second signal transmitted by the neighbormacro-BTS; determining, by the small scale base station, a set ofmeasurement data that includes, for each of the plurality of signalsreceived at the small scale base station, a corresponding measurementdata; and performing, by the small scale base station, location basedcalculations using the set of measurement data to determine thegeographic location of the small scale base station.
 2. The method asrecited in claim 1, wherein the set of measurement data comprises foreach received signal a fine of arrival.
 3. The method as recited inclaim 1, wherein the plurality of signals includes for each of aplurality of macro-BTSs a corresponding signal burst.
 4. The method asrecited in claim 1, wherein performing location based calculations usingthe set of measurement data to determine the geographic location of thesmall scale base station comprises reporting the set of measurement datato a another mobile network element.
 5. The method as recited in claim4, wherein the mobile network element is the SMLC, and wherein the SMLCuses the set of measurement data to determine the geographic location ofthe small scale base station.
 6. The method as recited in claim 1,wherein the set of measurement data includes, for each of a plurality ofpairs of macro-BTSs, a difference between a first time of arrival of afirst signal transmitted by a first macro-BTS included within a firstpair and a second time of arrival of a second signal transmitted by asecond macro-BTS included within the first pair.
 7. The method asrecited in claim 1, wherein determining the set of measurement datacomprises noting a respective difference in a time of arrival betweenthe plurality of signals received at the small scale base station. 8.The method as recited in claim 1, further comprising comparing thedetermined geographic location to an authorized geographic location. 9.The method as recited in claim 8, further comprising taking responsiveaction if it is determined that the determined geographic location isdifferent than the authorized geographic location.
 10. The method asrecited in claim 1, wherein the small scale base station is located inat least one of a residential building, a commercial building and anairport terminal.
 11. The method as recited in claim 1, wherein thesmall scale base station includes an RF sensing subsystem configured tosense an RF environment in a location where the small scale base stationis located.
 12. The method as recited in claim 1, wherein querying, bythe small scale base station, the SMLC includes determining a secondneighbor macro-BTS of the reference macro-BTS, and wherein the pluralityof signals received at the small scale base station includes a thirdsignal transmitted by the second neighbor macro-BTS.
 13. The method asrecited in claim 12, wherein performing location based calculationsusing the set of measurement data to determine the geographic locationof the small scale base station comprises performing E-OTD computations.14. The method as recited in claim 1, further comprising: determining,by the small scale base station, a geographic location of a second smallscale base station based on the determined geographic location of thesmall scale base station.
 15. A method of determining a geographiclocation of a small scale base station, the method comprising: querying,by the small scale base station, a serving mobile location center (SMLC)to determine a reference macro-base transceiver station (macro-BTS) anda neighbor macro-BTS of the reference macro-BTS; receiving a pluralityof signals at the small scale base station including a first signaltransmitted by the reference macro-BTS and a second signal transmittedby the neighbor macro-BTS; determining, by the small scale base station,a time of arrival, and corresponding assistance data, for each of theplurality of signals received at the small scale base station; andperforming, by the small scale base station, location based calculationsusing the time of arrival, and/or corresponding assistance data, foreach of the plurality of signals received at the small scale basestation to determine the geographic location of the small scale basestation.
 16. The method as recited in claim 15, further comprisingobtaining the corresponding assistance data from the SMLC that is used,along with the time, of arrival for each of the plurality of signalsreceived at the small scale base station, to determine the geographiclocation of the small scale base station.
 17. The method as recited inclaim 15, wherein querying, by the small scale base station, the SMLCincludes determining a second neighbor macro-BTS of the referencemacro-BTS, and wherein the plurality of signals received at the smallscale base station includes a third signal transmitted by the secondneighbor macro-BTS.
 18. The method as recited in claim 15, furthercomprising: determining, by the small scale base station, a geographiclocation of a second small scale base station based on the determinedgeographic location of the small scale base station.
 19. A system fordetermining a geographic location of a small scale base station, thesystem comprising: a radio frequency receiver; and a processorconfigured to: query a serving mobile location center (SMLC) todetermine a reference macro-base transceiver station (macro-BTS) and aneighbor macro-BTS of the reference macro-BTS; receive a plurality ofsignals including a first signal transmitted by the reference macro-BTSand a second signal transmitted by the neighbor macro-BTS; determine atime of arrival, and corresponding assistance data, for each of theplurality of received signals; and use the time of arrival, andcorresponding assistance data, for each of the plurality of receivedsignals to determine the geographic location of the small scale basestation.
 20. The system as recited in claim 19, further comprising acommunication interface coupled to the processor and wherein theprocessor is further configured to report to a core mobile networkelement via the communication interface the time of arrival, andcorresponding assistance data, for each of the plurality of receivedsignals.
 21. The system as recited in claim 20, wherein saidcommunication interface comprises an IP network interface and anaggregation gateway element (AGW), and wherein the AGW is configured toaggregate and translate traffic associated with the small scale basestation, via the IP network interface to the communication interface andto a base station controller.
 22. The system as recited in claim 19,wherein said radio frequency receiver and said processor are included insaid small scale base station.
 23. A system for determining a geographiclocation of a small scale base station, the system comprising: acommunication interface; and a processor configured to: query a servingmobile location center (SMLC) to determine a reference macro-basetransceiver station (macro-BTS) and a neighbor macro-BTS of thereference macro-BTS; receive a plurality of signals including a firstsignal transmitted by the reference macro-BTS and a second signaltransmitted by the neighbor BTS; receive via the communication interfacea set of measurement data that includes, for each of the plurality ofreceived signals, a corresponding measurement data; and use the set ofmeasurement data by performing location based calculations to determinethe geographic location of the small scale base station.
 24. The systemas recited in claim 23, wherein the communication interface and theprocessor comprise one or more of the following: a base stationcontroller, a mobile switching center, an SMLC, and an aggregatinggateway.
 25. A non-transitory computer program product for determining ageographic location of a small scale base station, the non-transitorycomputer program product being embodied in a memory and comprisingcomputer instructions for: querying a serving mobile location center(SMLC) to determine a reference macro-base transceiver station(macro-BTS) and a neighbor macro-BTS of the reference macro-BTS;receiving a plurality of signals including a first signal transmitted bythe reference macro-BTS and a second signal transmitted by the neighbormacro-BTS; receiving a set of measurement data that includes, each ofthe plurality of received signals, a corresponding measurement data; andperforming location based calculations at the small scale base stationusing the set of measurement data to determine the geographic locationof the small scale base station.
 26. A method of determining ageographic location of a small scale base station, the methodcomprising: determining, by a serving mobile location center (SMLC), areference location measurement unit (LMU) and a neighbor LMU of thereference LMU; receiving, at the SMLC, a first set of measurement datafrom the reference LMU and second set of measurement data from theneighbor LMU, wherein the first set of measurement data corresponds to aplurality of uplink transmissions received at the reference LMU, fromthe small scale base station, and the second set of measurement datacorresponds to a plurality of uplink transmissions received at theneighbor LMU, from the small scale base; determining, by the SMLC, athird set of measurement data corresponding to a difference between thefirst set of measurement data and the second set of measurement data;and performing location based calculations at the SMLC using the thirdset of measurement data to determine the geographic location of thesmall scale base station.
 27. The method as recited in claim 26, furthercomprising: determining, by the SMLC, a second neighbor LMU of thereference LMU; receiving, at the SMLC, a fourth set of measurement datafrom the second neighbor LMU, wherein the fourth set of measurement datacorresponds to a plurality of uplink transmissions received at thesecond neighbor LMU, from the small scale base station; determining, bythe SMLC, a fifth set of measurement data corresponding to a differencebetween the first set of measurement data and the fourth set ofmeasurement data; and performing location based calculations at the SMLCusing the fifth set of measurement data to determine the geographiclocation of the small scale base station.
 28. The method as recited inclaim 27, wherein determining the third and determining the fifth setsof measurement data comprise performing U-TDOA computations based on thefirst, second and fourth sets of measurement data, and wherein theplurality of uplink transmissions are initiated by forcing the smallscale base station into a temporary handover state to the reference LMU,the neighbor LMU, and the second neighbor LMU.